Other Important Aspects and Essays

Other also very important technological tests, are specially demanded for the qualification of the stones that are destined to the international markets. Such tests evaluate the resistance under impact (impact of hard body), the alteration by immersion in reactive liquid and the static deformability module, still determining the resistance of rupture under compression, after several freezing cycles and stone thawing, as well as the existence of discontinuities through the propagation speed of ultrasonic waves.

It is noticed that the constructions structures always "work", deforming as time goes by, there being differential movement relating to coverings and therefore compressive, distensible and flexion requests.

The physical-mechanical resistance to the rupture, whether by compression or flexion, as well as the capacity of elastic deformation (ductile) by effort or temperature variation, are altogether important for all situations of use of the stones in building construction.

Observing the inherent properties of these stones and their reactions, together with the adequate techniques of plastering, has increased the trustworthiness and durability of coverings, by preventing the risk of aesthetic alterations, rupture, displacement and/or fall of the plates.

Based upon technological tests realized by the Institute of Technological Research – IPT (Instituto de Pesquisa Tecnológica), on the main Brazilian lithological types used for ornamental and covering aims, the variation zones or average values achieved for different groups of stones are presented on Table 3.1. Table 3.2 discriminates the tests and analyses of interest for the qualification of stones suited to the use. Table 3.3 discriminates the different tests and essays, technical norms specifying them and the demandable results for some of them.

One of the new tests, very demanded for floor covering plates currently, is the "degree of slipperiness", that allows to evaluate the risk of falling for the walkers.(ver tabela)